Putin's spokesman rejects 'unfounded accusations' and ultimatums over UK poisoning
Russian President Vladimir Putin speaks with French President during a meeting at the Kremlin in Moscow on November 26, 2015 (AFP Photo/Sergei Chirikov)

Russian President Vladimir Putin's spokesman on Wednesday rejected what he called Britain's "unfounded accusations" and "ultimatums" over the poisoning of a former double agent in Britain.

"Moscow does not accept unfounded accusations that are not based on evidence and a language of ultimatums," Kremlin spokesman Dmitry Peskov told reporters.

"We are hoping that common sense will prevail," he said, in the Kremlin's first public response to British accusations that Russia could be behind the attempted murder of former double agent Sergei Skripal.

On Tuesday, Foreign Minister Sergei Lavrov rejected British Prime Minister Theresa May's deadline to explain how Skripal was poisoned in Britain with a highly toxic nerve agent invented by Russia.

"Moscow has nothing to do with the accident in Britain," Peskov said, reiterating that Moscow was open to cooperate on the investigation.

He declined to comment on calls in the West to possibly invoke NATO's principle of common defence, saying Moscow hopes that other countries would see there was no evidence to blame Russia for the poisoning attack.

"As far as a threat of isolation is concerned, we are hoping that common sense will prevail and other countries will at least think whether there is any proof or not and just how justified the rebukes against Moscow are," Peskov said.

- Russia slams May -

Lavrov on Wednesday criticised May, who had said Russia was "highly likely" to be behind the attack. He accused her of vagueness in her accusations.

"It is probably not very respectable and not very serious," he said, accusing the British government of making "political scenes."

He likened the British government to the notorious general prosecutor in Stalin's purge trials in the 1930s, Andrei Vyshinsky.

He was famous for coining the phrase "confession is the queen of evidence."

Lavrov said British authorities' tactics even topped those of Vyshinsky.

"For them the queen of evidence is not confession but suspicion, which they themselves are putting forward," he said.

"We will uphold international law," he said, adding that London will "be responsible for an open attempt to crudely mislead the global community."

London is considering possible punishment against Moscow.

British communications regulator Ofcom said it could review the licence of the Kremlin-backed RT broadcaster if Russian involvement in the poisoning were proven.

"Any illegal actions against any Russian media outlet in the United Kingdom will lead to retaliatory steps on the basis of reciprocity," Peskov said.

Russia has demanded that Britain give Moscow access to samples of the nerve agent used on Skripal and his daughter Yulia.

Foreign ministry spokeswoman Maria Zakharova said Wednesday that Russia still did not have the samples or their description.

"We received zero information from the British side despite our request," she told reporters.

"We don't even have access to the Russian national who suffered" in the attack, she added.

In a terse comment on the poisoning earlier this week, President Vladimir Putin told the BBC: "Sort things out from your side and then we will discuss this with you."